<template>
  <el-container class="home-container">
    <!-- 头部区域 -->
    <el-header>
      <div>
        <img src="../assets/img/heima.png" alt="" />
        <span>黑马后台管理系统</span>
      </div>
      <el-button type="info" @click="logout">退出</el-button>
    </el-header>
    <el-container>
      <!-- 侧边栏 -->
      <el-aside :width="isCollapse ? '64px' : '200px'">
        <div class="toggle-button" @click="toggleCollapse">|||</div>
        <!-- 菜单区域 -->
        <el-menu
          background-color="rgb(49, 55, 67)"
          text-color="#fff"
          active-text-color="#409eff"
          unique-opened
          :collapse="isCollapse"
          :collapse-transition="false"
          router
          :default-active="activePath"
        >
          <!-- 一级菜单 -->
          <el-submenu
            :index="item.id + ''"
            v-for="item in menuList"
            :key="item.id"
          >
            <template slot="title">
              <i :class="iconsObj[item.id]"></i>
              <span>{{ item.authName }}</span>
            </template>

            <!-- 二级菜单 -->
            <el-menu-item
              :index="subItem.path"
              v-for="subItem in item.children"
              :key="subItem.id"
              @click="saveNavState(subItem.path)"
            >
              <template slot="title">
                <i class="el-icon-menu"></i>
                <span>{{ subItem.authName }}</span>
              </template>
            </el-menu-item>
          </el-submenu>
        </el-menu>
      </el-aside>
      <!-- 主体区域 -->
      <el-main :first="first">
        <!-- 路由占位符，引入Welcome的内容 -->
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>
</template>

<script>
export default {
  data() {
    return {
      // 左侧菜单的数据
      menuList: [],
      // 一级菜单的字体符标
      iconsObj: {
        125: 'iconfont icon-user',
        103: 'iconfont icon-tijikongjian',
        101: 'iconfont icon-shangpin',
        102: 'iconfont icon-danju',
        145: 'iconfont icon-baobiao',
      },
      // 菜单是否折叠
      isCollapse: false,
      // 实现被选中的二级菜单的高亮
      activePath: '',
      // 实现点击按钮后，main区域的正确显示
      first: 1,
    }
  },
  // 在Home页面生成时立即执行
  created() {
    this.getMenuList()
    this.activePath = window.sessionStorage.getItem('activePath')
  },
  methods: {
    // 退出登录
    logout() {
      window.sessionStorage.clear('token')
      this.$router.push('/login')
    },
    // 获得左侧菜单的数据
    async getMenuList() {
      const { data: res } = await this.$http.get('menus')
      if (res.meta.status != 200) return this.$message.error(res.meta.msg)
      this.menuList = res.data
    },
    // 点击按钮，切换菜单的折叠与展开
    toggleCollapse() {
      this.isCollapse = !this.isCollapse

      // 实现点击按钮后，main区域的正确显示
      let main = document.querySelector('.el-main')
      if (this.first == 1) {
        main.style.left = '200px'
        this.first = 2
      }
      if (main.style.left == '200px') {
        main.style.left = '64px'
      } else {
        main.style.left = '200px'
      }
    },
    // 保存链接的激活状态，以实现被选中的二级菜单的高亮
    saveNavState(activePath) {
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath
    },
  },
}
</script>

<style lang="less" scoped>
.home-container {
  height: 100%;
}
.el-header {
  position: relative;
  width: 100%;
  height: 60px;
  background-color: rgb(54, 61, 64);
  display: flex;
  justify-content: space-between;
  padding-left: 0;
  align-items: center;
  color: #fff;
  font-size: 20px;

  div {
    display: flex;
    align-items: center;

    span {
      margin-left: 15px;
    }
  }
}
.el-aside {
  display: block;
  position: absolute;
  left: 0;
  top: 60px;
  bottom: 0;
  background-color: rgb(49, 55, 67);

  .toggle-button {
    background-color: #4a5064;
    text-align: center;
    font-size: 10px;
    line-height: 24px;
    color: #fff;
    letter-spacing: 0.2em;
    cursor: pointer;
  }

  .el-menu {
    border-right: 0;
  }
}
.el-main {
  position: absolute;
  left: 200px;
  right: 0;
  top: 60px;
  bottom: 0;
  overflow-y: scroll;
  background-color: rgb(233, 237, 240);
}

.iconfont {
  margin-right: 10px;
}
</style>
